Réponse :
Bonjour,
1/ He has lost his key
2/She has broken her leg.
3/She has improved her English.
4/His beard has grown.
5/The price of the bus fare has gone up.
6/ The temperature has dropped.
7/Somebody has turned it on.
Explications :
Present Perfect se forme avec l'auxiliaire have ( ou has à la troisième personne du singulier ) + verbe au participe passé ( 3ème colonne des verbes irrèguliers )